Realizing that with Blink of an Eye and Academy Journeymage blue probably doesn't need more bounce.

No idea what to replace Kamahl's Druidic Vow with, but boy is it bad.

Expedition Diviner is probably fairly strong support for UR Wizards, so I would rather swap Viashino Pyromancer for another 2-drop for goblins/aggro.
Artificer's Assistant was never a good payoff for historic and Silver Raven seems like a fine replacement.

I am not a fan of how many vanilla creatures there are in DOM, especially as most are understatted to boot.

Ancestral Blade may be too strong a common to replace knight with, but I like that it supports the equipment theme.

With Tormentor's Helm and Ancestral Blade, Short Sword can be replaced with a different utility artifact.

Testing supporting graveyard theme more with Eerie Soultender and Writhing Necromass.

I like Ghastly Gloomhunter as a replacement for a dumb 2/2 but it does mean black has two 2-drops that kick for .

Removal isn't the best in Dominaria and Snakeskin Veil feels like it would be too good in this environment. Powerstone Shard was never good, but I'm not sure what to replace it with, so I'm splitting the difference between a better mana rock and a creature. Gaea's Blessing never had a home, whereas The Weatherseed Treaty should fit right in.

I am not saying all the cards I am swapping in are correct, but the cards I am replacing definitely need to go.
Of note, for many of these replacements I tried to keep the new card similar in effect to the old. However, this was not always possible and sometimes the new card was selected more for archetype support.

Summary

White: Swapped out sideboard/weak spells for an aura for Boros and a cantrip.

Blue: Unsummon does a good Rescue impression, while not being the strongest card, but good support for spells decks.

Black: This color didn't have many unplayable cards. Finding a good replacement for Lich's Mastery was difficult. Right now I'm splitting the difference between Bolas's Citadel and Vilis, Broker of Blood.

Red: I like the idea of a possible Goblins deck so I made sure to replace Goblins with Goblins, ala Goblin Arsonist & Goblin Ringleader.

Green: In adding several noncreature spells I had to be aware of what effects I was adding to the set. I opted for a "bite" sorcery, and Broken Wings as a more main-deckable version of both Pierce the Sky/Broken Bond. I am uncertain on Snakeskin Veil.

This batch of common lands is primarily filled with utility lands, from cyclers to tapped lands with a beneficial etb.

I like having some common duals to help with a little splashing in the draft.

Memorial to War was disappointingly bad compared to the other Memorials. I couldn't find a good replacement but I think Keldon Megaliths is ok.
Likewise, Zhalfirin Void did not have enough upside or synergy to be worth running a colorless land, in a set with no colorless synergy. Buried Ruin, on the other hand, seems like an interesting pickup for decks with a few good artifacts.